Deformation of Median Nerve during Active and Passive Wrist Holding at Proximal Carpal Tunnel

Ping Yeap LOH,Satoshi MURAKI 대한인간공학회 2014 대한인간공학회 학술대회논문집 Vol.2014 No.5

The first objective of this study was to identify the deformation of the median nerve cross-sectional area (MNCSA) at different wrist active and passive holding positions. The second objective was to compare the wrist circumference, wrist width, and wrist depth between dominant and non-dominant hands. A total of eight right-handed healthy male adults (age 27.0 ± 3.5 years) participated in this study. Ultrasound examination was performed at the proximal carpal tunnel to examine the median nerve on the transverse plane. A total of three wrist positions were examined, namely, wrist neutral, wrist flexion 30°, and wrist extension 30°, in active and passive holding positions for both dominant and non-dominant hands. Paired t-test showed significant differences between dominant (D) and non-dominant (ND) hands in wrist circumference (D = 15.9 ± 0.6 cm, ND = 15.7 ± 0.6 cm, p<0.05), wrist width (D = 56.3 ± 3.6 mm, ND = 54.0 ± 2.1 mm, p<0.05), and wrist depth (D = 39.6 ± 2.8 mm, ND = 38.3 ± 2.7 mm, p<0.01). The differences of MNCSA between dominant and non-dominant hands were significant (p<0.001) at both active (D = 7.93 ± 0.63 mm<SUP>2</SUP>, ND = 6.98 ± 0.42 mm<SUP>2</SUP>) and passive holding positions (D = 8.22 ± 0.72 mm<SUP>2</SUP>, ND = 7.06 ± 0.44 mm<SUP>2</SUP>). Two-way repeated-measures ANOVA showed that wrist flexion 30° and wrist extension 30° caused significant reductions in MNCSA when compared with wrist neutral (p<0.001) in both active and passive holding positions. However, wrist active and passive holding did not have a significant effect on MNCSA changes. In conclusion, our findings showed that significant reduction of MNCSA was associated with wrist flexion-extension motion and there was significant bilateral asymmetry in physical characteristics of the wrist.

Deformation of Median Nerve during Active and Passive Wrist Holding at Proximal Carpal Tunnel

( Ping Yeap Loh ),( Satoshi Muraki ) 한국감성과학회 2014 춘계학술대회 Vol.2014 No.-

The first objective of this study was to identify the deformation of the median nerve cross-sectional area (MNCSA) at different wrist active and passive holding positions. The second objective was to compare the wrist circumference, wrist width, and wrist depth between dominant and non-dominant hands. A total of eight right-handed healthy male adults (age 27.0 ±3.5 years) participated in this study. Ultrasound examination was performed at the proximal carpal tunnel to examine the median nerve on the transverse plane. A total of three wrist positions were examined, namely, wrist neutral, wrist flexion 30°, and wrist extension 30°, in active and passive holding positions for both dominant and non-dominant hands. Paired t-test showed significant differences between dominant (D) and non-dominant (ND) hands in wrist circumference, wrist width, and wrist depth (D = 39.6 ± 2.8 mm, ND = 38.3 ± 2.7 mm, p<0.01). The differences of MNCSA between dominant and non-dominant hands were significant (p<0.001) at both active (D = 7.93 ± 0.63 mm2, ND = 6.98 ± 0.42 mm2) and passive holding positions (D = 8.22 ± 0.72 mm2, ND = 7.06 ± 0.44 mm2). Two-way repeated-measures ANOVA showed that wrist flexion 30° and wrist extension 30°caused significant reductions in MNCSA when compared with wrist neutral (p<0.001) in both active and passive holding positions.

Exploratory Study on the Impacts of Handle Vibration on the Hand and Forearm

Josefa Angelie Revilla,Ping Yeap Loh,Satoshi Muraki 대한산업공학회 2019 Industrial Engineeering & Management Systems Vol.18 No.4

This study investigated the immediate impacts of short-term handle vibration on hand functions, upper limb discomfort, and forearm muscle responses during hand grip test and task performance of seven healthy young adults. Thetask was to grip the handlebar for 5 minutes with 50% perceived strength under two conditions: with handle vibration(HV) and without handle vibration (NHV). Activities of forearm muscles namely flexor carpi radialis (FCR), flexor ofthe fingers (FF), flexor carpi ulnaris (FCU), and extensor digitorum (ED) were recorded using surface electromyography (EMG), while post-task hand tests for finger dexterity, strength, and sensibility were also measured. These fingerfunctions as well as muscle responses did not differ significantly between HV and NHV. The lacking effects might beassociated to the inconsistencies on grip force during task, perhaps participants let go of the handle during the latterpart. Meanwhile, perceived discomfort on the shoulder was significantly higher after HV than NHV and activity ofFCR, FF, and ED during maximal grip test were significantly different (p < 0.05) as well. Specifically, muscle activities were lower by 12-15% after HV than NHV, indicating that HV might have influenced the ability to grip hardly. Inconclusion, maximal grip test and discomfort rating can be a predictive parameter to determine the instantaneous effects of handle vibration.

보조적인 힘이 근장력 변동성의 크기와 불규칙성에 미치는 영향

최지원,Satoshi Muraki,Ping Yeap Loh 대한인간공학회 2024 大韓人間工學會誌 Vol.43 No.4

Objective: This study aims to observe how force output patterns alter when assistive force is provided during mechanically assisted force coordination with isometric elbow flexion. Background: Force coordination between humans and assistive robots requires human muscle force to be released in response to mechanical assistance. However, little is known about how motor performance of muscle force release with assistive force is different from the one without assistance. This study investigated how force variability parameters of coefficient of variation (CV) of force output, sample entropy, and stabilization time alter during isometric force control with assistive force. Method: Eleven male participants (mean: 24.4; SD: 1.5) participated in this experiment. Electromyography electrodes were placed on the surfaces of biceps and triceps muscles. The participant maintained an isometric elbow flexion force of 47N with the dominant arm along a linear trajectory shown on a screen. Under the conditions of assistive force provision, the assistive force was gradually provided as 25% or 50% of the isometric force for 0.5s by operating the actuator so that the participant could release their muscle force. Under the conditions where assistive force was not provided, the participant released their isometric force by 25% or 50% along with the visual guidance on the screen. From the manual force output, release stabilization time of force control was calculated and the CV and sample entropy were computed to represent size of force variability and time-series data irregularity, respectively. Results: Regardless of whether assistance was provided, the activation of biceps and triceps brachii muscles decreased after force release. This study found that compared to the visually guided conditions, mechanically assisted conditions showed a lower CV, longer stabilization time, and higher sample entropy. When the muscle force was greatly released (50% release of the isometric force), a longer stabilization time and greater CV were observed, but the entropy was lower compared to the slight muscle force release (25% release). Conclusion: This study suggests that when the magnitude of force release is relatively large, the size of force variability increases, while the irregularity decreases. This could imply that humans probably have potential adaptability for greater assistive force provided during mechanically assisted force coordination. Application: The results of the current study can be used to determine the amount of assistive force provided during human-robot collaboration.